St. Thomas would not have called himself a philosopher: his professional allegiance was to theology, and anyway in his view philosophers were pagan authorities. That did not prevent him, however, from using philosophy. Many of his writings show familiarity with philosophical works, have recognisable philosophical commitments, employ philosophical argument, and in some cases at least discuss particular philosophical works systematically and in great detail. As a result, Aquinas has frequently been promoted and assessed as a philosopher and now Pasquale Porro offers his contribution, a book written originally in Italian that examines the philosophical elements in St. Thomas's work and analyses them in their historical context.

Porro divides the book into six chapters. Each chapter focuses on an academically significant period of Aquinas's life and discusses his works from that time in chronological order. So the first chapter considers Aquinas's student years in Paris and Cologne culminating just prior to his inception as a Master of Theology (1245‐1256). It discusses De Principiis Naturae, De Ente et Essentia, and his Sentence‐Commentary. The second chapter covers Aquinas's first term as a regent in Paris (1256‐1259). It begins with a small discussion of Aquinas's defence of mendicant orders, Contra Impugnantes Dei Cultum et Religionem, but the bulk of the chapter deals with Quaestiones disputatae de Veritate, Quaestiones Quodlibeta VII‐XI, and the Commentary on Boethius's De Trinitate. The third chapter covers the period from the end of Aquinas's term as regent until his assignation to Rome (1259‐1265). It looks mainly at Summa contra Gentiles, but also discusses Aquinas's smaller and less well known Orvieto works such as Contra errores Graecorum. The fourth chapter examines the period from Aquinas's assignation to Rome in order to establish a Studium at Santa Sabina until his return to Paris (1265‐1268). It deals with Quaestiones disputatae de Potentia Dei and Summa Theologiae’s Prima Pars. It also discusses the problem of Aquinas's Alia Lectura, Super Librum Dionysii De Divinis Nominibus, Quaestiones disputatae de Anima, and a number of smaller works as well. The fifth chapter covers Aquinas's second term as regent in Paris (1268‐1272). It deals mainly with the Commentary on St. John's gospel, Quaestiones disputatae de Malo, Summa Theologiae’s Secunda Pars, Aquinas's second set of Quodlibeta i.e. I‐VI and XII, his Aristotelian Commentaries, especially those on The Physics and The Metaphysics, and his Commentary on Boethius's De Ebdomadibus. Again, like the other chapters, there is also a discussion of a number of less well known works. The sixth chapter covers the period after his second term as a regent until his death (1272‐1274). It discusses the end of Aquinas's life, his death, and the subsequent reception of his thought.

Much of the book is impressive. The justification in the author's preface for studying Aquinas as a philosopher (pp. ix‐xiii) is focused and correct. The discussion of mendicant/secular tensions in Paris at the time of Aquinas's inception is fascinating and helpful (pp. 53‐56). The historical context Porro brings to Aquinas's accounts in his Sentence‐commentary and Summa contra Gentiles of whether the Father's generation of the Word is personal or essential also deserves mention; Porro helpfully draws attention to Roger Marsden's report of the 1271/2 condemnation of the essentialist view, which both Aquinas and Peckham attended (pp. 140‐145). Helpful also is Porro's assessment of Aquinas's intention in writing the Aristotelian Commentaries (pp. 339‐340). Indeed, the coverage of Aquinas's works is so comprehensive that most readers will find value in it.

There are also matters to be concerned about in the book, however. First, several issues central to Aquinas's philosophical thought are not addressed. Thus there is no discussion of Aquinas's two attempts at deriving the categories in his Commentary on Metaphysics V and his Commentary on Physics III. There is no discussion of the relationship between the two accounts of individuation in De ente and Commentary on Boethius's De Trinitate. There is no discussion of how organized Aquinas thought the body must be in order for it to be disposed for the infusion of the rational soul. And there is no discussion of the composition of supposita, in particular whether Quodlibet II represents a change of mind on Aquinas's part.

Second, Porro's assessment of Aquinas's views is wrong on occasion. Thus for example Porro writes, ‘the difference between creator and creatures cannot be reduced to that between what is necessary and what is contingent, but must be located at another, more sophisticated level. Here we approach what is the real heart of thomistic metaphysics…’ (p. 149 Porro's emphasis). But this is wrong. If the actus essendi is intrinsic to God's essence and extrinsic to any creaturely essence, then there will be a sense of ‘contingent’ which is applicable to any creature but not to God, and a sense of ‘necessary’ which is applicable to God but not to any creature, and that will be the case regardless of the fact there is another sense of ‘contingent’ applicable only to material being. In that case ‘the difference between creator and creatures’ can be reduced ‘to that between what is necessary and what is contingent’. Nor is this just a semantic point; it goes to the heart of the metaphysical structure of created being, and Porro makes similar claims elsewhere in the book (c.f. pp. 147, 157, 405). Third, Porro should have consulted a broader range of secondary literature. Had he done so he could have utilised Dewan's work on De causis prop. 9, for example, and thus come to realise individuality is far more central to Aquinas's thought than he allows (p. 93).

Overall this is a good work with some weaknesses. It deserves a place on a course bibliography but not as a principal text. There are better works out there: Torrell's biography deals with the history better and Wippel's monograph deals with the philosophy better.